Vapor smoothing and post-processing glossary.

A

ABS Acrylonitrile butadiene styrene

An opaque, tough engineering thermoplastic used for housings, enclosures, fixtures and prototypes. It is printed by extrusion (FDM) and machined from sheet and rod. PostPro vapor smooths FDM-printed ABS with FA326 on the SF50 and SF100,¹ and vapor polishes machined ABS on the PostPro SF100 with PostPro Pure².

Acetone smoothing Hobby method

Exposing extrusion-printed ABS parts to acetone vapor in a jar or a heated box. It smooths the surface, but time, temperature and vapor concentration are not controlled and the solvent escapes into the room, so results vary from part to part. Industrial vapor smoothing runs the same idea as a controlled, closed machine process.

C

Closed loop Equipment

A vapor smoothing machine that keeps its finishing agent inside the system and recovers it after the cycle, instead of venting or discarding it. The PostPro SF50 and SF100: Closed-loop system with consumable recovery³.

Conditioning Cycle stage 01

The first stage of a PostPro cycle. Parts are conditioned in the chamber to reach the right processing conditions.³

Consumable See finishing agent

In vapor smoothing, the liquid finishing agent the machine vaporizes, plus wear items such as filters. See finishing agent.

Curing Cycle stage 03

The third stage of a PostPro cycle. The consumable is removed from the surface and the surface resolidifies.³

Cytotoxicity Testing

Whether a material damages living cells, tested in a lab on cell cultures. It matters for parts worn against the skin. In AMT’s published test on HP 3D HR PA 12 · HP MJF · PostPro Pure: No cytotoxic effects and no loss of strength⁴.

D

Dimensional change Measurement

How much a part’s measured dimensions differ after a process, usually given as a percentage. Vapor smoothing reflows a thin surface skin, so the change is small: ≤ 0.4%⁵2024 on PA12 · voxeljet HSS parts in AMT’s published test.

Drying Cycle stage 04

The last stage of a PostPro cycle. Parts are dried so no consumable remains in the chamber, ready for use.³

Dyeing Finishing method

Coloring parts in a heated dye bath. Dyeing changes color, not surface texture, and it is often combined with vapor smoothing. Compare finishing methods.

E

Elongation at break Measurement

How far a test bar stretches before it breaks, as a percentage of its starting length. A rough, notched surface makes parts break early; a smooth one lets them stretch further. In AMT’s published test on PA12 · voxeljet HSS: +38.1% (XY)⁵2024.

F

FA326 PostPro finishing agent

The PostPro agent with the longest material list: 100+ thermoplastics⁶, on the SF50 and SF100⁶.

FA9202 PostPro finishing agent

Dedicated consumable for finishing polypropylene parts¹. AMT lists it for the SFX, SF50, SF100⁶. Polypropylene vapor smoothing.

FDM Fused deposition modeling

Extrusion 3D printing: a heated nozzle lays down a thermoplastic filament line by line, leaving visible layer ridges. PostPro covers industrial FDM materials such as ULTEM and Onyx. Vapor smoothing industrial FDM parts.

Finishing agent Consumable

The liquid a vapor smoothing machine turns into vapor to smooth the part. PostPro uses three: PostPro Pure, FA326 and FA9202, each for a set of materials and machines.⁶ PostPro consumables.

Flame polishing Finishing method

Passing a torch flame over the edge of a plastic part, usually acrylic, so the surface melts and turns glossy. It works edge by edge, needs a skilled hand, and can bubble or stress the part; it cannot reach internal features. Compare vapor polishing.

Food-contact validation Testing

Lab testing that shows a finished material releases substances below the limits a food-contact regulation sets. For PostPro, one combination has been tested: FABULOUS DETECT PA11 · PostPro Pure, with Extractables well within regulatory limits under US FDA 21 CFR §177.1500⁷.

H

HMI Human-machine interface

The screen an operator uses to run a machine. The PostPro SF50 and SF100 have an HD touchscreen¹; the SFX a 7-inch touchscreen¹.

HSS High Speed Sintering

A powder-bed 3D printing process in which an inkjet head prints an absorbing ink and an infrared lamp fuses the inked powder. AMT has published vapor smoothing results on HSS PA12. Vapor smoothing SAF and HSS parts.

M

Media finishing Finishing method

Driving abrasive beads or grit at a part with compressed air to clean it and even out its surface. It leaves a uniform matte finish but does not seal it, and it reaches what the media can hit, no more. It is often the step before vapor smoothing or dyeing.

MES/ERP connectivity Equipment

A link between a machine and the factory’s manufacturing execution or planning software, so jobs and results are tracked. On the PostPro SF50 and SF100: MES/ERP connectivity¹.

MJF HP Multi Jet Fusion

HP’s powder-bed 3D printing process: agents are jetted onto a layer of powder and fused with infrared energy. MJF parts in PA12, PA11, TPU and polypropylene are vapor smoothed on PostPro systems.¹ Vapor smoothing MJF parts.

P

PA11 Polyamide 11, nylon

A nylon made from castor oil, tougher and more flexible than PA12. Printed by MJF · SLS · SAF · HSS⁶. PA11 vapor smoothing.

PA12 Polyamide 12, nylon

A widely used powder-bed 3D printing nylon, strong and dimensionally stable. Printed by MJF · SLS · SAF · HSS⁶. PA12 vapor smoothing.

PEI (ULTEM™) Polyetherimide

A high-heat, flame-resistant engineering plastic, printed by FDM and machined from stock. PostPro Pure handles FDM ULTEM parts and machined PEI.⁶ Vapor polishing machined PEI.

Polycarbonate (PC) Thermoplastic

A tough, clear plastic used for guards, covers and lenses. Machined PC turns frosted where the cutter passed; vapor polishing brings back the clarity. Vapor polishing polycarbonate.

Polypropylene (PP) Polyolefin

A light, chemically resistant plastic printed by MJF and SLS. Its resistance to solvents means it needs a dedicated finishing agent, FA9202. Polypropylene vapor smoothing.

Porosity Surface

The open pores in a powder-bed printed surface, where powder grains did not fully fuse. Pores take up water, dirt and dye. Vapor smoothing reflows the surface and closes them: Reduced surface porosity on UL94 V-0 flame-retardant parts⁸ (HP 3D HR PA 12 FR · HP MJF).

PostPro Brand

AMT’s brand of automated post-processing systems for 3D printed parts. The vapor smoothing range is the SFX, SF2X, SF50 and SF100.

PostPro Pure FA5802⁶

The finishing agent that runs in every PostPro vapor smoothing system (SFX, SF2X, SF50, SF100^1,6,9). Readily biodegradable (OECD 301 B)^10,1120242023. Hazard labels: Warning · H315 causes skin irritation · H319 causes serious eye irritation¹¹2023.

Powder-bed fusion 3D printing family

3D printing processes that fuse a thin layer of polymer powder at a time: MJF, SLS, SAF and HSS. Their parts come out with a grainy, porous surface, which is what vapor smoothing was built to finish.

Powder removal Preparation

Cleaning loose, unfused powder off powder-bed parts after printing. Parts are cleaned before vapor smoothing, so the vapor reaches the part’s real surface.

R

Ra Arithmetic mean roughness

The most quoted surface-roughness figure: the average distance of the measured surface profile from its mean line, in micrometers. Lower is smoother. Studies also use other parameters, so always check which one a figure uses.

RFID Equipment

Radio-frequency identification. PostPro SF systems use it for RFID consumable recognition and management³ and for RFID-controlled access¹.

S

SAF Selective Absorption Fusion

Stratasys’ powder-bed 3D printing process, in which an absorbing fluid and infrared energy fuse PA12 or PA11 powder. AMT has published process insights on vapor smoothing SAF parts with PostPro Pure.¹²

Sealing Surface

Closing the pores of a printed surface so water, sweat and dirt cannot get in. Vapor smoothing seals a part with its own reflowed material; a coating seals it with an added layer.

SLS Selective laser sintering

A powder-bed 3D printing process in which a laser fuses polymer powder, usually PA12 or PA11, layer by layer. Vapor smoothing SLS parts.

Surface roughness Measurement

A measure of the fine texture of a surface, taken with a stylus or optical profilometer and given in micrometers. In AMT’s published test on BASF Ultrasint TPU01 · HP MJF parts: 13.42 → 1.18 µm¹³2022, as printed to vapor smoothed. See Ra.

T

TPE Thermoplastic elastomer

The family of rubber-like plastics that can be melted and reshaped. Printed by MJF · SLS · SAF · FDM⁶. TPU and TPE vapor smoothing.

TPU Thermoplastic polyurethane

A flexible, hard-wearing elastomer used for seals, lattices, footwear and grips. Printed by MJF · SLS · SAF · HSS⁶. TPU vapor smoothing.

Tumbling Finishing method

Rotating or vibrating parts in a bowl of abrasive media for hours to round edges and smooth surfaces. It suits robust parts, rounds fine detail and leaves the surface open.

U

UL94 V-0 Flammability rating

The strictest of the vertical-burn V ratings in the UL94 plastics flammability standard: a test bar must stop burning quickly and not drip flaming particles. Protolabs vapor smooths flame-retardant PA12 parts that carry it.⁸

V

Vapor honing Not a vapor process

A wet abrasive finish, also called liquid honing: a slurry of water and fine media is driven at the part by compressed air. Despite the name, no solvent vapor is involved, and it does not reflow or seal plastic. Not to be confused with vapor polishing or vapor smoothing.

Vapor polishing Also vapour polishing

Reflowing the surface of a machined plastic part with a controlled solvent vapor to remove tool marks and bring back clarity, usually on polycarbonate and acrylic. AMT does it on the PostPro SF100 with PostPro Pure². Vapor polishing machined plastics.

Vapor smoothing Also vapour smoothing

A chemical finishing process for 3D printed polymer parts: a controlled solvent vapor softens the outer skin, the surface reflows and seals, and the bulk of the part keeps its shape. PostPro systems run it in four stages: Conditioning · processing · curing · drying³. What is vapor smoothing?